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    <title>Document</title>
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<body>
    <div>
        <ul>
            <li>hhh</li>
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    <script>
        var newli = document.createElement('li');//创建节点元素节点
        var ul = document.querySelector('ul');
        ul.appendChild(newli);//添加节点
        var lili = document.createElement('li');
        ul.insertBefore(lili,ul.children[0]);//从ul里面的第一个子节点前开始插入
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